The use of fiber composites for vehicle wheels or rims leads to marked improvements in terms of the acceleration and handling of a vehicle. The reduction of the inert and unsprung mass of the wheels leads at the same time to better road holding of the vehicle as well as to a great reduction of the bearing forces and can thus lead, for example, to prolonged service life of shock absorbers, wheel suspension and strut bearings.
Lightweight vehicle wheels, which consist fully or at least partly of fiber composite, have been known from the state of the art.
DE 41 23 459 C1 discloses a vehicle wheel, comprising a plastic rim and a wheel disk consisting at least partly of metal, with which a considerable weight reduction and at the same time sufficient thermal conductivity of the wheel can be achieved compared to conventional steel rims. The inner side of the rim, which consists of a high-strength plastic with relatively high thermal conductivity, is designed between the hump and well as an ideally shaped counterpart to the wheel disk, so that these are in contact with one another in a largely positive-locking manner. In addition, an inwardly directed, continuous or interrupted edge can be arranged on the side of the well facing away from the tire for screwing on the wheel disk. According to this document, a further positive-locking connection or connection in substance may be additionally provided between the rim and the wheel disk. To facilitate the flow of material, the wheel disk and the rim are especially preferably formed from a metal-plastic composite. The use of fiber composites is not disclosed in this document.
A vehicle wheel, comprising a rim made of fiber-reinforced plastic and a wheel disk made of metal, is described in DE 20 2005 004 399 U1. The wheel disk or spokes or other connection elements are connected centrally with the rim, and these are passed centrally through the rim. This solution is said to be advantageous over a fastening of the wheel disk to an edge located on the inner side, as in DE 41 23 459 C1. This is said to be especially apply to the tires of motorcycles, because unilateral stresses greatly stressing the rim mechanically are allegedly avoided by the central fastening. In addition, the problem that no rim is allegedly able to be manufactured with uniformly fiber-reinforced edge located on the inside according to the state of the art cited is said to be thus able to be bypassed.
DE 10 2010 010 513 A1 and DE 10 2010 010 512 A1 describe methods for manufacturing hollow section-like components, especially wheel rims, from fiber composites by the braiding deposition of fibers on a mold imaging the contour of the component and subsequent consolidation of this preform with matrix material. Furthermore, it is disclosed how a second component, especially a wheel disk or wheel brace or a wheel spider, can be integrated in the preform during the fiber deposition in a positive-locking manner in order to form a firm connection with the preform by connection in substance during the subsequent consolidation. Even though a high-strength connection of the wheel disk and rim is guaranteed hereby, this connection is based on an inseparable connection of the two components and thus makes a modular design of vehicle wheels by the combination of different wheel disks and rims impossible.
U.S. Pat. No. 3,917,352 describes a vehicle wheel made of fiber-reinforced plastic wheel as well as a method for manufacturing same. The wheel is of a one-part design and comprises both rim well and wheel disk. The manufacture of the wheel is carried out by winding a fabric tube around the two halves of a mold, where the wheel disk can be formed by winding over a groove. However, the fiber deposition during winding does not take place in a sufficiently positive-locking manner, and the fabric tube must therefore be wound additionally around with fabric tape or filaments. Due to the fact that the manufacturing method is limited to one-part rims, a modular design of vehicle wheels is not possible.
DE 42 23 290 B4 discloses a composite synthetic resin wheel, which comprises a plurality of partial cast parts. The partial cast parts have corresponding threads on their connection surfaces, so that they can be fitted together by means of screw connection. This type of joining, which deviates from the industrial standard, requires the preparation of the threads already at the time of the manufacture of the partial cast parts and this greatly limits the possibility of using them. The manufacture of parts with such threads is not readily possible, moreover, without casting or injection molding methods.
Lightweight wheels made of fiber composites have hitherto been mainly niche products and are often prohibitively expensive for the regular consumer because of the small batch numbers and the high manufacturing costs. This is due especially to the fact that the manufacture of rims from fiber composites requires not only technical know-how, but also special machines and technologies, which are appearing in series production only slowly. The introduction of this technology on the mass market could, however, be substantially facilitated by modular systems, which make it possible for the various manufacturers to resort to a selection of basic elements and to individualize these elements.